1. Field of the Invention
The invention relates to a semiconductor device for use in a large scale integration circuit (IC), and more particularly to a semiconductor device having insulated gate field effect transistors (IGFETS) such as metal-oxide-semiconductor field effect transistors (MOSFETS) and complementary MOSFETS
2. Description of the Prior Art
Using metal-oxide semiconductor (MOS) IC technology, a large number of field effect transistors (FETS), may have been integrated in a semiconductor chip. As a result, many input and output terminals are required to connect the internal circuits of the semiconductor chip to external devices. It is clear that the number of these terminals is in proportion to the quantity of information which is to be processed in the device. Therefore, a large number of terminals will be required in a large scale integration circuit device. Each terminal is connected to a bonding pad on a semiconductor chip, respectively. The bonding pad in turn is connected to an interface element (for example, a buffer element) which is also on the chip. The interface element has, in general, a terminal (i.e. a bonding pad or the like) and an input and/or output buffer circuit. The terminal is connected to one end portion of the input and/or output buffer transistor, while the other end of the input and/or output buffer transistor is connected to an internal processing circuit such as a register circuit or a latch circuit. Since this interface element is associated with each terminal, an increase in the number of terminals increases the chip size. However, increasing the chip size is undesirable because it decreases the production yield rate while increasing cost. Particularly, when the buffer element is formed using complementary MOS (CMOS) technology, a P-channel MOS transistor and an N-channel MOS transistor are used as a buffer circuit and are respectively positioned at both sides of a bonding pad. Therefore, increasing the number of terminals (or input/output bits) is a significant problem in CMOS IC devices.
An object of the present invention is to provide a semiconductor device in which the size of a buffer element is reduced.
Another object of the present invention is to provide an MOS IC device in integrated circuit form having many input/output buffer elements, each of which has a bonding pad and an input/output buffer circuit.